Answer:
[tex]\large\boxed{(x^3)(-x^3y)^2=x^9y^2}[/tex]
Step-by-step explanation:
[tex](x^3)(-x^3y)^2\qquad\text{use}\ (ab)^n=a^nb^n\\\\=(x^3)(-x^3)^2(y^2)\qquad\text{use}\ (a^n)^m=a^{nm}\\\\=(x^3)(x^6)(y^2)\qquad\text{use}\ a^n\cdot a^m=a^{n+m}\\\\=x^{3+6}y^2\\\\=x^9y^2[/tex]
